Medical treatment devices having adjustable length and/or diameter

ABSTRACT

The present embodiments enable the length and/or diameter of the heating segment of a medical treatment device to be adjusted on the fly during a treatment procedure, without a need to interrupt the procedure, thus allowing a single catheter to be used at different locations in a hollow anatomical structure.

TECHNICAL FIELD

The present embodiments relate to medical treatment devices,particularly medical treatment devices having adjustable length and/ordiameter.

BACKGROUND

Various endovenous treatments are commonly used for treating venousreflux disease, and other diseases of hollow anatomical structures(HAS). Venous reflux disease is a disease caused by damaged vein valves,which typically prevent blood from flowing backwards in a vein. Thus,with damaged valves, particularly in the legs, gravity works against theblood flowing upward toward the heart, resulting in venous congestionand varicose veins. Varicose veins typically happen in superficialveins, such as the Greater Saphenous Vein (GSV) and the Lesser SaphenousVein (LSV), creating unsightly and painful bulges and tortuous veins,and may lead to many serious complications.

Electrosurgical heating is one endovenous treatment for venous refluxdisease, as well as other diseases in HAS. Electrosurgical heating mayuse radio frequency current to apply energy to create targeted tissueablation to seal off damaged veins. Electrosurgical equipment typicallyincludes a generator, such as an RF generator, and a catheter having aheating segment located at the distal end, which is inserted into thevein(s) during treatment. The heating segment may use RF energy drivenby the RF generator to heat and seal the vein. Currently, the cathetersinclude a heating segment having a fixed length, such as 7 cm, 4 cm, 3cm, and a specific combination of length and diameter, for example, 7Fon a 7 cm catheter, 5F on a 3 cm catheter, or 3F on a 1 cm catheter. (Findicates the French scale for measuring the outside diameter of acatheter, 1F=0.33 mm.)

However, the Saphenous Vein length and diameter varies at the thigh,calf and ankle portions and from patient to patient. For example, theGreater Saphenous Vein may range in diameter from about 2.5 to 14.0 mmat the femoral junction, 1.5 to 12.0 mm in the thigh, and 1.0 to 8.0 mmin the calf, while Lesser Saphenous Vein diameters may range from 1.5 to3.0 mm. Often, there may be a need for treating these various sizes in asingle patient in a single procedure.

SUMMARY

The various embodiments of the present medical treatment devices havingadjustable length and/or diameter have several features. Withoutlimiting the scope of the present embodiments as expressed by the claimsthat follow, their features now will be discussed briefly. Afterconsidering this discussion, and particularly after reading the sectionentitled “Detailed Description,” one will understand how the features ofthe present embodiments provide the advantages described herein.

One of the present embodiments comprises an adjustable-dimensioncatheter for tissue ablation. The catheter comprises an elongate shafthaving a distal end and a proximal end. The catheter further comprises ashaft connector adjacent the distal end of the shaft, the shaftconnector having a plurality of shaft electrical contacts. The catheterfurther comprises a first heating assembly having a first heatingelement having a first length and a first diameter at a distal endthereof, and a first heating element connector adjacent a proximal endthereof, the first heating element connector having a plurality of firstheating element electrical contacts having a first heating elementelectrical contact configuration. The catheter further comprises asecond heating assembly having a second heating element having a secondlength and a second diameter at a distal end thereof, and a secondheating element connector adjacent a proximal end thereof, the secondheating element connector having a plurality of second heating elementelectrical contacts having a second heating element electrical contactconfiguration. The first and second heating element connectors areselectively connectable to the shaft connector at the distal end of theshaft to selectively couple the first and second heating assemblies tothe shaft. At least one of the first and second lengths and the firstand second diameters of the first and second heating elements aredifferent. The first and second heating element electrical contactconfigurations are different, such that the first heating elementelectrical contacts contact a first combination of the shaft electricalcontacts of the shaft connector when the first heating element connectoris connected to the shaft connector, and the second heating elementelectrical contacts contact a second combination of the shaft electricalcontacts of the shaft connector when the second heating elementconnector is connected to the shaft connector, and the first and secondcombinations of the shaft electrical contacts are different.

The shaft electrical contacts and the first and second heating elementelectrical contacts may have a stepped configuration in which thecontacts are spaced in the axial direction and at least two of thecontacts are spaced in the radial direction.

The heating elements may comprise an electrically resistive element.

The electrically resistive element may be a coil.

The catheter may further comprise an indicator adjacent a proximal endof the shaft that indicates which of the first and second heatingelements is connected to the shaft.

Another of the present embodiments comprises an adjustable-dimensioncatheter for tissue ablation. The catheter comprises an elongate shafthaving a distal end and a proximal end. The catheter further comprises ashaft connector adjacent the distal end of the shaft, the shaftconnector having a plurality of shaft electrical contacts. The catheterfurther comprises a plurality of heating assemblies, each comprising aheating element of a different length at a distal end thereof, and eachhaving a heating element connector adjacent a proximal end thereof, eachof the heating element connectors having a plurality of heating elementelectrical contacts. The heating element connectors are selectivelyconnectable to the shaft connector at the distal end of the shaft toselectively couple the heating assemblies to the shaft. The heatingelement electrical contacts on each of the heating assemblies havedifferent configurations, such that the heating element electricalcontacts on each of the heating assemblies contact a differentcombination of the shaft electrical contacts of the shaft connectordepending on a length of a given one of the heating elements.

The catheter may further comprise a power source configured toautomatically detect a length of a connected one of the heating elementsand adjust a level of power delivery for a desired energy output.

The shaft electrical contacts and the heating element electricalcontacts may have a stepped configuration in which the contacts arespaced in the axial direction and at least two of the contacts arespaced in the radial direction.

The catheter may further comprise a first set of screw threads on theshaft connector and mating second sets of screw threads on the heatingelement connectors.

The heating elements may comprise at least one radio frequency (RF)electrode.

The heating elements may comprise an electrically resistive element.

The heating elements may each comprise a different diameter.

The catheter may further comprise an indicator adjacent a proximal endof the shaft that indicates which of the heating elements is connectedto the shaft.

The indicator may comprise at least one light-emitting diode (LED).

The indicator may comprise a plurality of differently colored LEDs.

Another of the present embodiments comprises a set of heating assembliesconfigured to be secured to a catheter. The set of heating assembliescomprises at least a first heating assembly having a first heatingelement of a first length and a first diameter at a distal end thereof,and a first heating element connector adjacent a proximal end thereof,the first heating element connector having a plurality of first heatingelement electrical contacts having a first heating element electricalcontact configuration. The set of heating assemblies further comprisesat least a second heating assembly having a second heating element of asecond length and a second diameter at a distal end thereof, and asecond heating element connector adjacent a proximal end thereof, thesecond heating element connector having a plurality of second heatingelement electrical contacts having a second heating element electricalcontact configuration. The first and second heating element connectorsare selectively connectable to a shaft connector at a distal end of thecatheter to selectively couple the first and second heating assembliesto the shaft. At least one of the first and second lengths and the firstand second diameters of the first and second heating elements aredifferent.

The first and second heating element electrical contacts may have astepped configuration in which the contacts are spaced in the axialdirection and at least of the two contacts are spaced in the radialdirection.

The heating elements may comprise an electrically resistive element.

The electrically resistive element may be a coil.

The set of heating assemblies may further comprise a first set of screwthreads on the first heating assembly a second set of screw threads onthe second heating assembly.

Another of the present embodiments comprises a method for tissueablation. The method comprises connecting a first heating element havinga first length and a first diameter to a distal end of an elongateshaft. The method further comprises ablating tissue with the firstheating element. The method further comprises disconnecting the firstheating element from the shaft. The method further comprises connectinga second heating element having a second length and a second diameter tothe distal end of the shaft, wherein the first and second lengths andthe first and second diameters are different. The method furthercomprises ablating tissue with the second heating element. When thefirst heating element is connected to the shaft, heating elementelectrical contacts on the first heating element contact a firstcombination of shaft electrical contacts on the shaft, and when thesecond heating element is connected to the shaft, heating elementelectrical contacts on the second heating element contact a secondcombination of the shaft electrical contacts on the shaft.

When either of the heating elements is connected to the shaft, a powersource may automatically detect at least one of a length and a diameterof the connected one of the heating elements and adjust a level of powerdelivery for a desired energy output.

The shaft and heating element electrical contacts may have a steppedconfiguration in which the contacts are spaced in the axial directionand also in the radial direction.

Connecting the heating elements to the distal end of the shaft maycomprise connecting a first set of screw threads on the distal end ofthe shaft to second sets of screw threads on the heating elements.

The heating elements may comprise at least one radio frequency (RF)electrode.

The heating elements may comprise an electrically resistive element.

The electrically resistive element may be a coil.

The method may further comprise indicating which of the heating elementsis connected to the shaft via an indicator adjacent a proximal end ofthe shaft.

The indicator may comprise at least one light-emitting diode (LED).

Another of the present embodiments comprises a method for tissueablation. The method comprises connecting a first heating segment havinga first length and a first diameter to a distal end of an elongateshaft. The method further comprises ablating tissue with the firstheating segment. The method further comprises disconnecting the firstheating segment from the shaft. The method further comprises connectinga second heating segment having a second length and a second diameter toa distal end of the shaft, wherein the first and second lengths and thefirst and second diameters are different. The method further comprisesablating tissue with the second heating segment. When the first heatingsegment is coupled to the shaft, the heating segment electrical contactsof the first heating segment are electrically connected to one of aplurality of different combinations of the shaft electrical contactsdepending on a length of the first heating segment.

When either of the first and second heating segments is connected to theshaft, a power source may automatically detect at least one of a lengthand a diameter of the connected one of the heating segments and adjust alevel of power delivery for a desired energy output based on thedetected length.

The shaft and heating segment electrical contacts may have a steppedconfiguration in which the contacts are spaced in the axial directionand also in the radial direction.

Connecting the first and second heating segments to the distal end ofthe shaft may comprise connecting a first set of screw threads on thedistal end of the shaft to second sets of screw threads on the heatingsegments.

The heating segments may comprise at least one radio frequency (RF)electrode.

The heating segments may comprise an electrically resistive element.

The method may further comprise indicating which of the heating segmentsis connected to the shaft via an indicator adjacent a proximal end ofthe shaft.

The indicator may comprise at least one light-emitting diode (LED).

Another of the present embodiments comprises a medical treatment devicehaving an adjustable treatment diameter. The device comprises a catheterhaving an elongate flexible shaft with a proximal end and a distal end.The device further comprises a first electrically resistive heatingelement disposed at the distal end of the shaft, the first electricallyresistive heating element having a first outer diameter. The devicefurther comprises first electrical contacts on the catheter shaft. Thedevice further comprises a second electrically resistive heating elementhaving a second, larger, outer diameter and connectable to the shaft toat least partially surround the first electrically resistive heatingelement, the second electrically resistive heating element having secondelectrical contacts connectable to the first electrical contacts.

The first and second electrically resistive heating elements may becoils.

The device may be in combination with a power source, wherein the powersource is configured to automatically detect whether the secondelectrical contacts are connected to the first electrical contacts andadjust an energy output to the second heating element to a desiredenergy output.

Detecting whether the second electrical contacts are connected maycomprise measuring at least one of a resistance value and an inductancevalue of the second heating element by passing a detecting currentthrough the second heating element.

The second heating element may be connectable to the distal end of theshaft by one of a screw joint, or a latch joint.

Another of the present embodiments comprises a medical treatment devicehaving an adjustable treatment diameter. The device comprises a catheterhaving an elongate flexible shaft with a proximal end and a distal end.The device further comprises a first heating element disposed at thedistal end of the shaft, the first heating element having a first outerdiameter. The device further comprises first electrical contacts on thecatheter shaft. The device further comprises a second heating elementhaving second electrical contacts connectable to the first electricalcontacts, the second heating element having a second outer diameter thatis greater than the first outer diameter.

When the second electrical contacts are connected to the firstelectrical contacts the second heating element may at least partiallysurround the first heating element.

The device may be in combination with a power source, wherein the powersource is configured to automatically detect whether the secondelectrical contacts are connected to the first electrical contacts andadjust an energy output to the second heating element to a desiredenergy output.

Detecting whether the second electrical contacts are connected maycomprise measuring at least one of a resistance value and an inductancevalue of the second heating element by passing a detecting currentthrough the second heating element.

The second heating element may be connectable to the distal end of theshaft by one of a screw joint, or a latch joint.

The device may further comprise a third heating element having thirdelectrical contacts connectable to the first electrical contacts, thethird heating element having a third outer diameter that is greater thanthe second outer diameter.

Another of the present embodiments comprises a medical treatment devicehaving an adjustable treatment diameter. The device comprises a catheterhaving an elongate flexible shaft with a proximal end and a distal end.The device further comprises a first heating element disposed at thedistal end of the shaft, the first heating element having a first outerdiameter. The device further comprises a second heating elementconnectable to the distal end of the shaft over the first heatingelement, the second heating element having a second outer diameter thatis greater than the first outer diameter.

The device may be in combination with a power source, wherein the powersource is configured to automatically detect whether the second heatingelement is connected to the distal end of the shaft and adjust an energyoutput to the second heating element to a desired energy output.

Detecting whether the second heating element is connected may comprisemeasuring at least one of a resistance value and an inductance value ofthe second heating element by passing a detecting current through thesecond heating element.

The device may further comprise electrical contacts on the shaft, theelectrical contacts configured to electrically connect the secondheating element to a power source.

The power source may be configured to automatically detect whether thesecond heating element is connected to the electrical contacts andadjust an energy output to the second heating element to a desiredenergy output.

Detecting whether the second heating element is connected to theelectrical contacts may comprise detecting whether a detecting currentis flowing between the electrical contacts.

Detecting whether the second heating element is connected to theelectrical contacts may comprise measuring at least one of a resistancevalue and an inductance value of the second heating element by passing adetecting current through the second heating element.

The second heating element may be connectable to the distal end of theshaft by one of a screw joint, or a latch joint.

The device may further comprise a third heating element connectable tothe distal end of the shaft over the first heating element, the thirdheating element having a third outer diameter that is greater than thesecond outer diameter.

The second heating element may comprise an inner diameter greater thanor equal to the first outer diameter of the first heating element.

Another of the present embodiments comprises a method for tissueablation. The method comprises positioning a first heating elementadjacent to a target tissue, the first heating element disposed at adistal end of an elongate shaft, wherein the elongate shaft includes aproximal end and the distal end, and the first heating element having afirst outer diameter. The method further comprises ablating the targettissue with the first heating element. The method further comprisesconnecting a second heating element to the distal end of the shaft overthe first heating element, the second heating element having a secondouter diameter that is greater than the first outer diameter. The methodfurther comprises ablating a second target tissue with the secondheating element.

The method may further comprise detecting with a power source connectedto the proximal end of the shaft whether the second heating element isconnected to the shaft and adjusting an energy output to a desiredenergy output.

Detecting whether the second heating element is connected may comprisemeasuring at least one of a resistance value and an inductance value ofthe second heating element by passing a small current through the secondheating element.

The method may further comprise disconnecting the second heating elementfrom the shaft and connecting a third heating element to the shaft, thethird heating element having a third outer diameter that is greater thanthe second outer diameter.

Another of the present embodiments comprises a tissue treatment device.The device comprises an elongate shaft having a distal end. The devicefurther comprises a heating element disposed at the distal end of theshaft, the heating element having a proximal end and a distal end. Thedevice further comprises a first electrical pathway configured to extendbetween a power source, the proximal end of the heating element, and thedistal end of the heating element, and defining a first treatment lengthextending between the proximal and distal ends of the heating element.The device further comprises a second electrical pathway configured toextend between the power source, the distal end of the heating element,and an intermediate point along the heating element intermediate theproximal and distal ends thereof, and defining a second treatment lengthextending between the intermediate point and the distal end of theheating element.

The device may further comprise a switch configured for selection ofpower delivery to the first electrical pathway or the second electricalpathway.

The power source may be configured to automatically distinguish betweenthe first and second treatment lengths and adjust a level of powerdelivery for a desired energy output.

The heating element may be an electrically resistive heating element.

The heating element may be an electrically resistive coil.

Another of the present embodiments comprises a tissue treatment device.The device comprises an elongate shaft having a distal end. The devicefurther comprises a heating element disposed at the distal end of theshaft, the heating element having a proximal end and a distal end. Thedevice further comprises a first electrical pathway configured to extendbetween a power source, the proximal end of the heating element, and thedistal end of the heating element, and defining a first treatment lengthextending between the proximal and distal ends of the heating element.The device further comprises a second electrical pathway configured toextend between the power source, the proximal end of the heatingelement, and an intermediate point along the heating element between theproximal and distal ends thereof, and defining a second treatment lengthextending between the intermediate point and the proximal end of theheating element.

The device may further comprise a switch configured for selection ofpower delivery to the first electrical pathway or the second electricalpathway.

The power source may be configured to automatically distinguish betweenthe first and second treatment lengths and adjust a level of powerdelivery for a desired energy output.

The heating element may be an electrically resistive heating element.

The heating element may be an electrically resistive coil.

Another of the present embodiments comprises a method for tissuetreatment. The method comprises positioning a catheter having anelongate shaft with a heating element disposed at a distal end thereofsuch that the heating element is adjacent a first treatment site in ahollow anatomical structure (HAS). The method further comprisesdelivering power during a first power delivery phase from a power sourceconnected to the heating element along a first electrical pathwayextending between the power source, a proximal end of the heatingelement, and a distal end of the heating element, thereby defining afirst treatment length between the distal and proximal ends of theheating element. The method further comprises moving the catheter alongthe HAS such that the heating element is adjacent a second treatmentsite in the HAS. The method further comprises delivering power during asecond power delivery phase from the power source along a secondelectrical pathway extending between the power source, a distal end ofthe heating element, and an intermediate point along the heating elementintermediate the proximal and distal ends thereof, thereby defining asecond treatment length between the intermediate point and the distalend of the heating element.

Delivering power during the second power delivery phase may compriseswitching power delivery from the first electrical pathway to the secondelectrical pathway.

The power source may be configured to automatically distinguish betweenthe first and second treatment lengths and adjust a level of powerdelivery for a desired energy output.

The heating element may be an electrically resistive heating element.

The heating element may be an electrically resistive coil.

Another of the present embodiments comprises a method for tissueablation. The method comprises positioning a catheter having an elongateshaft with a heating element disposed at a distal end thereof such thatthe heating element is adjacent a first treatment site in a hollowanatomical structure (HAS). The method further comprises deliveringpower during a first power delivery phase from a power source connectedto the heating element along a first electrical pathway extendingbetween the power source, a proximal end of the heating element, and adistal end of the heating element, thereby defining a first treatmentlength between the distal and proximal ends of the heating element. Themethod further comprises moving the catheter along the HAS such that theheating element is adjacent a second treatment site in the HAS. Themethod further comprises delivering power during a second power deliveryphase from the power source along a second electrical pathway extendingbetween the power source, a proximal end of the heating element, and anintermediate point along the heating element intermediate the proximaland distal ends thereof thereby defining a second treatment lengthbetween the intermediate point and the proximal end of the heatingelement.

Delivering power during the second power delivery phase may compriseswitching power delivery from the first electrical pathway to the secondelectrical pathway.

The power source may be configured to automatically distinguish betweenthe first and second treatment lengths and adjust a level of powerdelivery for a desired energy output.

The heating element may be an electrically resistive heating element.

The heating element may be an electrically resistive coil.

Another of the present embodiments comprises a method of varying atreatment length of a heating element disposed at a distal end of atissue treatment device. The method comprises delivering power to theheating element during a first power delivery phase, wherein the poweris delivered from a power source along a first electrical pathwayextending between the power source, a proximal end of the heatingelement, and a distal end of the heating element, thereby defining afirst treatment length between the distal and proximal ends of theheating element. The method further comprises delivering power to theheating element during a second power delivery phase wherein the poweris delivered from the power source along a second electrical pathwayextending between the power source, a distal end of the heating element,and an intermediate point along the heating element intermediate theproximal and distal ends thereof, thereby defining a second treatmentlength between the intermediate point and the distal end of the heatingelement.

Delivering power during the second power delivery phase may compriseswitching power delivery from the first electrical pathway to the secondelectrical pathway.

The power source may be configured to automatically distinguish betweenthe first and second treatment lengths and adjust a level of powerdelivery for a desired energy output.

The heating element may be an electrically resistive heating element.

The heating element may be an electrically resistive coil.

Another of the present embodiments comprises a method of varying atreatment length of a heating element disposed at a distal end of atissue treatment device. The method comprises delivering power to theheating element during a first power delivery phase, wherein the poweris delivered from a power source along a first electrical pathwayextending between the power source, a proximal end of the heatingelement, and a distal end of the heating element, thereby defining afirst treatment length between the distal and proximal ends of theheating element. The method further comprises delivering power to theheating element during a second power delivery phase wherein the poweris delivered from the power source along a second electrical pathwayextending between the power source, a proximal end of the heatingelement, and an intermediate point along the heating elementintermediate the proximal and distal ends thereof, thereby defining asecond treatment length between the intermediate point and the proximalend of the heating element.

Delivering power during the second power delivery phase may compriseswitching power delivery from the first electrical pathway to the secondelectrical pathway.

The power source may be configured to automatically distinguish betweenthe first and second treatment lengths and adjust a level of powerdelivery for a desired energy output.

The heating element may be an electrically resistive heating element.

The heating element may be an electrically resistive coil.

The present embodiments enable the length and/or diameter of the heatingsegment of a medical treatment device to be adjusted on the fly during atreatment procedure, without a need to interrupt the procedure. Suchadjustability enables a single catheter to be used at differentlocations in a hollow anatomical structure (HAS) where the length and/ordiameter of a portion of the HAS to be treated may vary.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments of the present medical treatment devices havingadjustable length and/or diameter now will be discussed in detail withan emphasis on highlighting the advantageous features. These embodimentsare for illustrative purposes only. These drawings include the followingfigures, in which like numerals indicate like parts:

FIG. 1 is an overview of a medical treatment system having an adjustablelength and/or diameter;

FIGS. 1A and 1B are side elevation views of an example procedure usingthe medical treatment system of FIG. 1;

FIG. 2 is a side elevation view of one embodiment of a medical treatmentdevice having an adjustable treatment length;

FIG. 3 is a schematic diagram of a first configuration for powerdelivery to the medical treatment device of FIG. 2;

FIG. 4 is a schematic diagram of a second configuration for powerdelivery to the medical treatment device of FIG. 2;

FIG. 5 is a schematic diagram of a third configuration for powerdelivery to the medical treatment device of FIG. 2;

FIG. 6 is a side elevation view of one embodiment of a portion of amedical treatment device having an adjustable treatment length;

FIG. 7 is a side elevation view of one embodiment of another portion ofthe medical treatment device of FIG. 6 having an adjustable treatmentlength;

FIG. 8 is a side elevation view of one embodiment of another portion ofthe medical treatment device of FIG. 6 having an adjustable treatmentlength;

FIG. 9 is a side elevation view of one embodiment of another portion ofthe medical treatment device of FIG. 6 having an adjustable treatmentlength;

FIG. 10 is a circuit diagram of one embodiment of an electrical circuitconfigured for use in the medical treatment device of FIGS. 6-9;

FIG. 11 is a side perspective view of one embodiment of a portion of amedical treatment device having an adjustable treatment diameter;

FIG. 12 is a side perspective view of one embodiment of another portionof the medical treatment device of FIG. 11 having an adjustabletreatment diameter;

FIG. 13 is a side perspective view of the portions of FIGS. 11 and 12together;

FIG. 14A is a front elevation view of one embodiment of a pin connectorconfigured to connect to a chip for detecting a type of catheter and/orheating segment attached to the power source; and

FIG. 14B is a side elevation view of one embodiment of a chip fordetecting a type of catheter and/or heating segment attached to thepower source.

DETAILED DESCRIPTION

The following detailed description describes the present embodimentswith reference to the figures. In the figures, reference numbers labelelements of the present embodiments. These reference numbers arereproduced below in connection with the discussion of the correspondingfeatures.

Directional terms used herein, such as proximal, distal, upper, lower,clockwise, counterclockwise, etc., are used with reference to theconfigurations shown in the figures. For example, a component that isdescribed as rotating clockwise when viewed from the perspectives shownin the figures may be said to rotate counterclockwise when viewed fromthe opposite perspective. Furthermore, the present embodiments may bemodified by altering or reversing the positions or directions ofmovement of various components. Accordingly, directional terms usedherein should not be interpreted as limiting.

Referring to FIG. 1, a medical treatment system 10 may include acatheter shaft 12 having a distal end 13 and a proximal end 14. Aheating segment 15 is operably attached adjacent the distal end 13 ofthe catheter shaft 12 and a handle 16 is attached at the proximal end 14of the catheter shaft 12. A cable 17 electrically connects the heatingsegment 15 to a power source 18. The cable 17 may be integral to thehandle 16 and removably connected to the power source 18. Alternatively,the cable 17 may be removably connected to the handle 16.

The heating segment 15 includes a heating element. The heating elementmay in some embodiments be a resistive coil, which may be driven, forexample, by RF energy, ultrasound, or any other electrical form.Preferably, the relative resistance or impedance of the heating elementis designed to correlate to, or match, the power source 18 to which theheating element is coupled. For example, the resistance of the heatingelement may be determined by a wire gage that relates to the catheterdiameter, the energy required during treatment, and/or the power sourcespecifications. The heating element may comprise a wide variety ofconductive materials, such as, for example, nickel chromium (NICHROME®),Alloy 52, copper, stainless steel, titanium, zirconium, NITINOL®,ALUMEL®, KANTHANAL®, CHROMEL®, KOVAR®, combinations or alloys of thesame and the like. The material for the heating element can be chosen toprovide Resistance Temperature Detector (RTD) functionality, whereintemperature is indirectly measured as a function of impedance. Alloy 52is considered to be one material suitable for providing RTDfunctionality to the resistive coil.

The heating segment 15 is secured at the distal end 13 of the elongatecatheter shaft 12. The catheter shaft 12 may be used to maneuver theheating element into a desired placement within a HAS. In certainembodiments, the catheter shaft 12 comprises a biocompatible materialhaving a low coefficient of friction. For example, the shaft maycomprise polyether ether ketone (PEEK), polyethylene, orpolytetrafluoroethylene (PTFE), such as TEFLON®. In other embodiments,the catheter shaft 12 may comprise polyimide, thermoplastic elastomer(TPE), such as HYTREL®, polyether block amide (PEBA), such as PEBAX®,nylon, or any other such suitable material.

In certain embodiments, the catheter shaft 12 is sized to fit within avascular structure that may be between approximately 1 mm andapproximately 25 mm in diameter and, preferably, between approximately 2mm and approximately 18 mm. For instance, the catheter shaft 12 may havea maximum outer diameter of between approximately 4F (French) andapproximately 8F and, more preferably, between approximately 6F andapproximately 7F. In yet other embodiments, other sizes of catheters maybe used. The proximal end 14 of the catheter shaft includes a handle 16that may include a connection for interfacing with the power source 18through the cable 17, and/or a port for fluid or guidewire passage.

In certain embodiments, the power source 18 comprises an alternatingcurrent (AC) source, such as an RF generator. In other embodiments, thepower source 18 comprises a direct current (DC) power supply, such as,for example, a battery, a capacitor, or other power source 18 such aswould be used for microwave heating. The power source 18 may alsoincorporate a controller that, through the use of a processor, appliespower based at least upon readings from a temperature sensor or sensors(e.g., a thermocouple, a thermistor, a resistance temperature device, anoptical or infrared sensor, combinations of the same or the like)located in or adjacent to the heating segment 15. For example, thecontroller may heat the tissue of a HAS or the heating segment 15 to aset temperature. In an alternative embodiment, the user selects aconstant power output of the power source 18. For example, the user maymanually adjust the power output relative to the temperature displayfrom a temperature sensor in the heating segment 15.

The medical treatment system 10 may be used in various medicalprocedures, including endovenous treatments to treat venous reflux.Specifically, referring to FIG. 1A, a method may comprise inserting theheating segment 15 into a distal-most section of a HAS 19 to be treated.The heating segment 15 is then aligned with a first treatment locationT1 within the HAS 19. In certain embodiments, a tumescent solution maybe injected to surround and compress the HAS 19 (assisting in evacuationof fluid from within the HAS 19, providing a thermal heat sink toprotect surrounding tissue, and providing anesthetic to the surroundingtissue). Compression of the HAS 19, such as through manual compressionby the physician, may also be performed.

Power is then applied to the heating segment 15 for a desired length oftime to treat the first treatment location T1. After a desired dwelltime, such as after the HAS 19 has collapsed as shown in FIG. 1B, thepower supply to the heating segment 15 may be reduced or shut off. Withthe power off (or substantially reduced), the heating segment 15 maythen be moved proximally until the distal end of the heating segment 15is adjacent to the proximal end of the first treatment location T1, asshown in FIG. 1B. At this second treatment location T2 within the HAS19, power is again applied to the heating segment 15 for a desiredlength of time to treat the HAS 19 at the second treatment location T2.This process is repeated until the treatment of the HAS 19 is complete.In some embodiments, T1 and T2 may overlap. While T1 and T2 are shownadjacent to one another in the same HAS, T1 and T2 may be in differentlocations, such as different HAS. For example, as may be appreciatedfrom the description below, T1 may be in the GSV, while T2 may be in aperforator vein flowing into the GSV, which may require devices ofdifferent length and/or diameter.

Adjustable Length Medical Treatment Devices

In clinical practice, such as for treating chronic venous insufficiency,the Great Saphenous Vein (GSV), the Small Saphenous Vein (SSV), and theSuperficial Tributary Vein (STV) may all need to be treated in a singleprocedure. But, the lengths of these veins are different from oneanother. The example embodiment of FIGS. 2-5 is a medical treatmentdevice having an adjustable treatment length, and is configured to solvethe foregoing problem. In certain embodiments, the medical treatmentdevice is a catheter configured for tissue ablation, but the inventiveconcepts of the present embodiments could be applied to other types ofmedical treatment devices.

With reference to FIGS. 1 and 2, the heating segment 15 comprises atreatment device 20 including a heating element 22 having a proximal end24 and a distal end 26. In the illustrated embodiment, the heatingelement 22 is an electrically resistive coil that heats up when electriccurrent is delivered to it from the power source 18. However, in otherembodiments the heating element 22 may comprise another type of deviceconfigured to heat tissue.

The illustrated treatment device 20 further includes a plurality ofwires 28, 30, 32 extending between the power source 18 and the heatingelement 22, and electrically connected to the heating element 22. Thewires 28, 30, 32 are configured to carry electrical current between thepower source 18 and the heating element 22. The wires 28, 30, 32 arefurther configured to provide a plurality of electrical pathwaysextending between the power source and heating element 22, as explainedin further detail below. In some embodiments, the wires 28, 30, 32 maybe welded to the heating segment 22, such as by laser spot welding,resistance spot welding, etc. In other embodiments the wires 28, 30, 32may be soldered to the heating element 22.

A first one of the wires 28 extends between the power source 18 and thedistal end 26 of the heating element 22. A second one of the wires 30extends between the power source and the proximal end 24 of the heatingelement 22. A third one of the wires 32 extends between the power source18 and a point 34 along the heating element 22 intermediate the proximaland distal ends 24, 26 thereof. Current may be selectively applied toeach of the wires 28, 30, 32 to create electrical pathways of differentlengths, and thereby selectively change the effective length of theheating element 22.

For example, current may be applied through the first and second wires28, 30 only (see FIG. 3), such that an electrical pathway extendsbetween the power source 18, the proximal end 24 of the heating element22, and the distal end 26 of the heating element 22, thereby defining afirst treatment length L1 extending between the proximal and distal ends24, 26 of the heating element 22. In another example, current may beapplied through the first and third wire 28, 32 only (see FIG. 4), suchthat an electrical pathway extends between the power source 18, thedistal end 26 of the heating element 22, and the intermediate point 34,thereby defining a second treatment length L2 extending between theintermediate point 34 and the distal end 26 of the heating element 22.In yet another example, current may be applied through the second andthird wire 30, 32 only (see FIG. 5), such that an electrical pathwayextends between the power source, the proximal end 24 of the heatingelement 22, and the intermediate point 34, thereby defining a thirdtreatment length L3 extending between the intermediate point 34 and theproximal end 24 of the heating element 22.

With reference to FIG. 2, in certain embodiments the intermediate point34, where the third wire 32 is electrically connected to the heatingelement 22, may be offset from a lengthwise center of the heatingelement 22. In such embodiments, three different treatment lengths maybe achieved, because a distance L3 between the proximal end 24 and theintermediate point 34 is different from a distance L2 between the distalend 26 and the intermediate point 34 (with the entire length L1 of theheating element 22 providing the third treatment length). In otherembodiments, however, the intermediate point 34 may be at the lengthwisecenter of the heating element 22, such that L2 and L3 are the samelength.

The present embodiments may include one or more switching mechanisms 36(FIGS. 3-5) to select which of the treatment lengths is active at anygiven moment. The switching mechanism 36 may be on the handle 16, or maybe part of the power source 18, such as part of a controller or asindividual switches. For example, FIGS. 3-5 schematically illustrate thethree electrical pathways described above. With reference to FIG. 3, theswitching mechanism 36 closes the circuit between the power source 18and the first and second wires 28, 30, thereby creating an electricalpathway between the power source 18, the proximal end 24 of the heatingelement 22, and the distal end 26 of the heating element 22. Withreference to FIG. 4, the switching mechanism 36 closes the circuitbetween the power source 18 and the first and third wires 28, 32,thereby creating an electrical pathway between the power source 18, theintermediate point 34 of the heating element 22, and the distal end 26of the heating element 22. With reference to FIG. 5, the switchingmechanism 36 closes the circuit between the power source 18 and thesecond and third wires 30, 32, thereby creating an electrical pathwaybetween the power source 18, the intermediate point 34 of the heatingelement 22, and the proximal end 24 of the heating element 22.

In certain embodiments, the power source 18 may be configured toautomatically distinguish between the various treatment lengths L1, L2,L3 and adjust a level of power delivery for a desired energy output. Forexample, in certain embodiments an impedance value of the heatingelement 22 may be measured to determine the treatment length.Alternatively, if the heating element 22 is a coil, it will generate amagnetic field when it is energized. The length of the heating element22 can then be determined by measuring the strength of the magneticfield. In another alternative, a switch may be provided on the handle 16to indicate the treatment length. In yet another alternative, powerdelivery to the heating element 22 can be adjusted automatically toadapt different treatment lengths based on temperature feedback fromtemperature sensors located in the heating element 22.

In certain embodiments, the maximum power output to the heating element22 is 65 W, and the target temperature of the heating element 22 is 120°C. For example, in various methods the temperature of the heatingelement 22 may increase from ambient temperature to 120° C. in 5seconds, and be maintained at 120° C. for another 15 seconds. The systemmay adjust the power output automatically according to a temperaturefeedback loop, such as with a temperature sensor located in or near theheating element 22. Normally, during the temperature ramp up period (thefirst 5 s), a greater amount of power is supplied to the heating elementas compared to the temperature maintenance period (the last 15 s).

The embodiments of FIGS. 2-5 may be used in a variety of methods,including treatment procedures such as tissue ablation to treat venousreflux, as described above (FIGS. 1A-1B). For example, one such methodmay comprise positioning the heating element 22 of the device of FIG. 2adjacent a first treatment location T1 in a hollow anatomical structure.Power may then be delivered during a first power delivery phase from apower source 18 connected to the heating element 22 along the firstelectrical pathway extending between the power source 18, the proximalend 24 of the heating element 22, and the distal end 26 of the heatingelement 22, thereby defining a first treatment length L1 between theproximal and distal ends 24, 26 of the heating element 22. Power maythen be delivered during a second power delivery phase from the powersource 18 along the second electrical pathway extending between thepower source 18, the distal end 26 of the heating element 22, and theintermediate point 34 on the heating element 22, thereby defining thesecond treatment length L2 between the distal end 26 of the heatingelement 22 and the intermediate point 34. The foregoing method mayfurther comprise, between the first and second power delivery phases,positioning the heating element 22 adjacent to a second treatmentlocation T2 in the HAS, and switching power delivery from the firstelectrical pathway to the second electrical pathway. In one example, theheating element 22 may be positioned in a perforator vein connecting thetarget HAS and the deep venous system. Typically, the perforator vein isshorter than the target HAS, and thus might require a shorter length ofthe heating element 22 to be used. The heating element 22 may then bepulled back into the target HAS and the procedure continued within thetarget HAS using a longer length of the heating element 22. In analternative embodiment, the second power delivery phase may comprisedelivering power from the power source along the third electricalpathway extending between the power source 18, the proximal end 24 ofthe heating element 22, and the intermediate point 34 on the heatingelement 22, thereby defining the third treatment length L3 between theproximal end 24 of the heating element 22 and the intermediate point 34.Other embodiments may comprise methods of varying a treatment length ofa tissue ablation catheter.

Adjustable Length and/or Diameter Medical Treatment Devices

The embodiment of FIGS. 6-10 is another example embodiment of a heatingsegment 15 having an adjustable treatment length, as well as anadjustable treatment diameter, comprising a shaft connector 40 andvarious heating assemblies 58, 60, 62. As in the embodiment of FIGS.2-5, the present device includes an elongate catheter shaft 12, thefeatures and configuration of which may be similar to that describedabove. Also as in the embodiment of FIGS. 2-5, the present device isconnectable to a power source 18, the features and configuration ofwhich may be similar to that described above.

With reference to FIG. 6, the shaft connector 40 is secured adjacent thedistal end 13 of the catheter shaft 12. In the illustrated embodiment,the shaft connector 40 comprises a substantially cylindrical body 42having a plurality of shaft electrical contacts 44, 46, 48 near aproximal end 50 of the shaft connector 40. The shaft electrical contacts44, 46, 48 have a stepped configuration in which the contacts are spacedin the axial direction and also in the radial direction. In theillustrated embodiment, three shaft electrical contacts 44, 46, 48 areshown, but in alternative embodiments any number of shaft electricalcontacts 44, 46, 48 may be provided.

As illustrated, the shaft electrical contacts 44, 46, 48 comprise aplurality of rings, each having a progressively greater diameter in theproximal-to-distal direction, and each being axially spaced. Aproximal-most ring comprises a first shaft electrical contact 44, acentral ring comprises a second shaft electrical contact 46, and adistal-most ring comprises a third shaft electrical contact 48.Insulating rings 52 are interposed between adjacent shaft electricalcontacts 44, 46, 48. The stepped proximal end 50 of the shaft connector40 is configured to mate with a coupler at a proximal end of each of aplurality of heating assemblies, as described further below.

The shaft connector 40 further comprises a shaft mechanical coupler 54at a distal end 56 of the shaft connector 40. The illustrated embodimentof the shaft mechanical coupler 54 comprises a plurality of internalscrew threads, but in alternative embodiments may comprise otherstructures, such as latches. The shaft mechanical coupler 54 isconfigured to mate with a coupler at a proximal end of each of theplurality of heating assemblies.

The shaft connector 40, including the electrical contacts 44, 46, 48,the insulators 52, and the cylindrical body 42, may comprise anysuitable materials. For example, the cylindrical body 42 may be apolymer, which may be plated with a metal, such as stainless steel. Theelectrical contacts 44, 46, 48 may be metallic, such as iron, gold,copper, etc. The insulators 52 may be rubber or plastic, for example.

With reference to FIGS. 7-9, the present heating segment 15 furthercomprises a plurality of heating assemblies 58, 60, 62, each having adifferent length and/or diameter. In the illustrated embodiment, threeheating assemblies 58, 60, 62 are shown, but in alternative embodimentsany number of heating assemblies 58, 60, 62 may be provided with thecatheter 12. Each of the heating assemblies 58, 60, 62 has a heatingelement connector 64 adjacent a proximal end 66 thereof, with each ofthe heating element connectors 64 having a plurality of heating elementelectrical contacts 68, 70, 72. Each of the heating assemblies 58, 60,62 further includes a heating assembly mechanical coupler 74 adjacentthe proximal end 66, but distal of the heating element electricalcontacts 68, 70, 72. The heating element connectors 64 are connectableto the shaft connector 40 to selectively couple the heating assemblies58, 60, 62 to the catheter shaft 12, as described further below.

The heating element electrical contacts 68, 70, 72 have a steppedconfiguration in which the contacts are spaced in the axial directionand also in the radial direction, and are configured to be complementaryto the shaft electrical contacts 44, 46, 48. In the illustratedembodiment, three heating element electrical contacts 68, 70, 72 areshown for each of the heating assemblies 58, 60, 62, but in alternativeembodiments any number of heating element electrical contacts may beprovided. Also in the illustrated embodiment, the heating elementmechanical coupler 74 comprises a plurality of external screw threadsthat mate with the shaft mechanical coupler 54 to releasably couple theheating assemblies 58, 60, 62, to the shaft connector 40. Alternativeembodiments may comprise other structures to mate with the shaftmechanical coupler 54, such as latches.

With further reference to FIGS. 7-9, the proximal end 66 of each of theheating assemblies 58, 60, 62 includes a proximal-most or firstelectrical contact 68, a distal-most or third electrical contact 72, andan intermediate or second electrical contact 70. Insulating rings 76 areinterposed between adjacent heating element electrical contacts 68, 70,72. The diameters of the heating element electrical contacts 68, 70, 72vary from one embodiment to another, such that the heating elementelectrical contacts 68, 70, 72 achieve electrical connection with theshaft electrical contacts 44, 46, 48 in various combinations.

For example, with the shaft connector 40 releasably engaged with theproximal end 66 of the heating assemblies 58, 60, 62, the heatingelement electrical contacts 68, 70, 72 are configured to selectivelycontact various combinations of the shaft electrical contacts 44, 46, 48in order to modulate the power delivery to the heating assemblies 58,60, 62 based upon the length of the heating assemblies 58, 60, 62.

Distally of the heating element mechanical coupler 74, each heatingassembly 58, 60, 62 further comprises a heating element 78. In theillustrated embodiment, the heating element 78 is an electricallyresistive element, such as an electrically restrictive coil, but inother embodiments may comprise other structures, such as one or moreradio frequency (RF) electrodes. In FIGS. 7-9, each of the heatingelements 78 is illustrated with a different length, with the embodimentof FIG. 7 having the greatest length L4, the embodiment of FIG. 9 havingthe shortest length L6, and the embodiment of FIG. 8 having a length L5intermediate of FIGS. 7 and 9. Each heating assembly 58, 60, 62 also hasa diameter D4, D5, D6, respectively, which may also be different. Incertain embodiments, only the length L4, L5, L6 of the heating elements78 vary. In other embodiments, only the diameters D4, D5, D6 of theheating elements 78 vary. In still other embodiments, both the lengthL4, L5, L6 and the diameters D4, D5, D6 of the heating elements 78 vary.Each of the heating assemblies 58, 60, 62 further has a differentconfiguration at the stepped proximal end 66, such that the heatingelement electrical contacts 68, 70, 72 will contact the shaft electricalcontacts 44, 46, 48 in different ways as each heating element 78 issequentially connected to the shaft connector 40, as described below.

With reference to FIG. 7, the first, second, and third heating elementelectrical contacts 68, 70, 72 are sized and configured to be matinglyreceived within the corresponding first, second and third shaftelectrical contacts 44, 46, 48 such that electrical contact is achievedbetween all electrical contacts on each component. When so connected,the power source 18 detects that all of the shaft electrical contacts44, 46, 48 are in electrical connection with all of the heating elementelectrical contacts 68, 70, 72, and adjusts the power output accordinglyto deliver a desired level of treatment power based on the length L4 ofthe heating element 78.

With reference to FIG. 8, the first and third heating element electricalcontacts 68, 72 are sized and configured to be matingly received withinthe corresponding shaft electrical contacts 44, 48 such that electricalcontact is achieved between only the first and third electrical contactson each component (the second electrical contacts on each component arenot connected). When so connected, the power supply detects that onlythe first and third shaft electrical contacts 44, 48 are in electricalconnection with only the first and third heating element electricalcontacts 68, 72, and adjusts the power output accordingly to deliver adesired level of treatment power based on the length L5 of the hearingelement 78.

With reference to FIG. 9, the second and third heating elementelectrical contacts, 70, 72 are sized and configured to be matinglyreceived within the corresponding second and third shaft electricalcontacts 46, 48 such that electrical contact is achieved between onlythe second and third electrical contacts on each component (the firstelectrical contacts on each component are not connected). When soconnected, the power supply detects that only the second and third shaftelectrical contacts 46, 48 are in electrical connection with only thesecond and third heating element electrical contacts 70, 72, and adjuststhe power output accordingly to deliver a desired level of treatmentpower based on the length L6 of the heating element 78.

With respect to the embodiment of FIGS. 6-9, certain embodiments maycomprise an indicator adjacent a proximal end of the catheter shaft 12that indicates which of the heating assemblies 58, 60, 62 is connectedto the shaft. As discussed above, the power source 18 automaticallydetects which of the heating assemblies 58, 60, 62 is connected at anygiven time and adjusts the power output accordingly. Upon determiningwhich of the heating assemblies 58, 60, 62 is connected, the powersource 18 may also set a visual appearance of the indicator accordingly.For example, the indicator may comprise one or more light-emittingdiodes (LEDs) 82, (see FIG. 10), such as a plurality of monochromatic orpolychromatic LEDs. In one embodiment comprising three heatingassemblies 58, 60, 62, the indicator may comprise three LEDs of the samecolor, and a single one of the LEDs may be illuminated when the shortestheating element 78 is connected, three of the LEDs may be illuminatedwhen the longest heating element 78 is connected, and two of the LEDsmay be illuminated when the intermediate length heating element 78 isconnected.

FIG. 10 is a circuit diagram 80 showing one example of an alternativeembodiment having two LEDs 82A, 82B, and specifically how the threeelectrical contacts on both the shaft connector 40 and the heatingassemblies 58, 60, 62 can trigger three connection conditions to controlwhich of the two LEDs 82A, 82B is illuminated. In FIG. 10, RF power isgenerated using power from power supply VCC_(—)15V. Power for LED 82A isprovided by a PORTRIGHT-L connection and power for LED 82B is providedby a PORTLEFT-L connection. JOINTS I, II, and III correspond toconnections provided by the electrical connectors discussed with respectto FIGS. 6-9. As an example, when connecting junction points JOINT I andJOINT III, electrical power from PORTRIGHT-L passes through R3, LED A82A, D7, L1, and Q1 to ground. LED A 82A is thus illuminated to indicatethat the heating assembly 60 of FIG. 8 is connected. When connectingjunction points JOINT II and JOINT III, electrical power from PORTLEFT-Lpasses through R4, LED B 82B, D9, L1, and Q1 to ground. LED B 82B isthus illuminated to indicate that the heating assembly 62 of FIG. 9 isconnected. When connecting junction points JOINT I, JOINT II, and JOINTIII, both the LED A 82A and LED B 82B circuits are activated and bothLED A 82A and LED B 82B are illuminated to indicate that the heatingassembly 58 of FIG. 7 is connected. RF energy is activated fromVCC_(—)15V via Q2, D6, and/or D8, L1, and Q1 to ground, to achieve RFenergy delivery to the coil. During actual RF energy delivery, LED A 82Aand/or LED B 82B will be off, since the RF voltage is higher than theLED driving voltage at JOINT I and/or JOINT II.

The embodiment of FIGS. 6-9 may be used in a variety of methods,including treatment procedures such as tissue ablation to treat venousreflux, as described above with reference to FIG. 1A. For example, onesuch method may comprise connecting a first heating assembly 58 having aheating element with a first length L4 to a distal end of an elongatecatheter shaft 12, and ablating tissue with the first heating element 78at a first treatment location T1. The first heating assembly 58 may thenbe disconnected from the catheter shaft 12, and a second heatingassembly 60 having a heating element 78 with a second length L5 may beconnected to the distal end of the catheter shaft 12. The first andsecond lengths L4, L5 may be different. The method may further compriseablating tissue with the second heating element 60 at a second treatmentlocation T2. When the first heating assembly 58 is connected to thecatheter shaft, heating element electrical contacts 68, 70, 72 on thefirst heating assembly 58 may contact a first combination of shaftelectrical contacts 44, 46, 48 on the shaft. When the second heatingassembly 60 is connected to the catheter shaft 12, heating elementelectrical contacts 68, 70, 72 on the second heating assembly 60 maycontact a second combination of the shaft electrical contacts 44, 46,48. When any of the heating assemblies 58, 60, 62 is connected to thecatheter shaft 15, a power source 18 coupled to the device mayautomatically detect a length of the connected heating element 78 basedon which of the shaft electrical contacts 44, 46, 48 is in contact withthe heating element electrical contacts 68, 70, 72. In response, thepower supply 18 may adjust a level of power delivery for a desiredenergy output.

Adjustable Diameter Medical Treatment Devices

As described above, the Great Saphenous Vein (GSV), the Small SaphenousVein (SSV), and the Superficial Tributary Vein (STV) may all need to betreated in a single procedure. But, the diameters of these veins aredifferent from one another. The example embodiment of FIGS. 11-13 is amedical treatment device having an adjustable treatment diameter, and isconfigured to solve the foregoing problem. In certain embodiments, themedical treatment device is a catheter configured for tissue ablation asdescribed above, but the inventive concepts of the present embodimentscould be applied to other types of medical treatment devices.

FIGS. 11-13 illustrate one example embodiment of a medical treatmentdevice having an adjustable treatment diameter. With reference to FIG.11, the device includes a flexible, tubular catheter shaft 90 having anominal diameter heating element 92 at a distal end 94. In theillustrated embodiment, the nominal diameter heating element 92 is aresistive heating coil that encircles the catheter 90. However, in otherembodiments the nominal diameter heating element 92 may comprise anothertype of treatment device, such as one or more electrodes. The nominaldiameter heating element 92 has an outer diameter, referred to herein asa nominal diameter D1, that may be for example 5F. Electricallyconductive wires 96 extend through the catheter shaft 90 in order toconnect the nominal diameter heating element 92 to a power source 18. Atemperature sensor (not shown), such as a thermocouple, may also beprovided so that temperature at a treatment site may be monitored.

With further reference to FIG. 11, an outer surface of the cathetershaft 90 includes a pair of electrical contacts 98 located proximally ofthe nominal diameter heating element 92. In the illustrated embodiment,the contacts 98 are spaced radially by 90°, but in alternativeembodiments could be configured differently such as different radialspacing or axial spacing. The electrical contacts 98 provide connectionpoints for a larger diameter heating element 100, which is illustratedin FIG. 12 and which can be attached to the catheter 90 when needed. Theelectrical contacts 98 are also connected to the power source 18 throughthe wires 96, so that the power source can deliver power to the largerdiameter heating element 100.

With further reference to FIG. 12, the larger diameter heating element100 has a diameter D2 larger than that of the nominal diameter heatingelement 92. For example, the diameter of the larger diameter heatingelement 100 may be 7F. The larger diameter heating element 100 is thusadapted to treat larger hollow anatomical structures. The largerdiameter heating element 100 includes a pair of electrical contacts 102at its proximal end 104 that are positioned to achieve removableelectrical connection with the electrical contacts 98 on the cathetershaft 90 when the larger diameter heating element 100 is positionedaround the distal end 94 of the catheter 90 over the nominal diameterheating element 92, as shown in FIG. 13. While not shown, a mechanicalcoupling may be provided to secure the larger diameter heating segment100 to the catheter 90, such as a screw joint, a latch joint, a magneticclip, or any other mechanical or electromechanical method. In additionto being of a larger diameter, larger diameter heating element 100 mayalso have a longer length, as shown.

In certain embodiments, the power source 18 may be configured toautomatically detect whether the larger diameter heating element 100 isconnected to the distal end 94 of the catheter shaft 90, and to adjustan energy output to the larger diameter heating element 100 to a desiredenergy output. For example, detecting whether the larger diameterheating element 100 is connected may comprise measuring at least one ofa resistance value and an inductance value of the larger diameterheating element 100 by passing a detecting current through the largerdiameter heating element 100. In an alternative embodiment, detectingwhether the larger diameter heating element 100 is connected maycomprise detecting whether a detecting current is flowing between theelectrical contacts 98 on the catheter 90.

While the illustrated embodiment shows only one larger diameter heatingelement 100, the present embodiments may include any number of largerdiameter heating elements of various diameters. Each such element may beconnectable to the catheter shaft 90 sequentially to further enhance theadaptability of the treatment device to various different applicationsat different locations in the body, or to accommodate unexpected largervasculature of a patient without the need to open another completedevice having a different diameter during the procedure.

The embodiment of FIGS. 11-13 may be used in a variety of methods,including treatment procedures such as tissue ablation to treat venousreflux, as described above with reference to FIGS. 1A and 1B. Forexample, one such method may comprise positioning a nominal diameterheating element 92 adjacent to a first treatment location T1, whereinthe first heating element 92 is disposed at a distal end 94 of anelongate catheter shaft 90, and the nominal diameter heating element 92has a first outer diameter D1. The target tissue may then be ablatedwith the nominal diameter heating element 92. A larger diameter heatingelement 100 may then be connected to the distal end 94 of the shaft overthe nominal diameter heating element 92. The larger diameter heatingelement 100 has a second outer diameter D2 that is greater than thefirst outer diameter D1. A second treatment location T2 may then beablated with the larger diameter heating element 100. Alternatively, thelarger diameter heating element 100 may be used first, then removed totreat smaller HAS.

In certain embodiments, the method may further comprise detecting with apower source 18 connected to the proximal end of the catheter shaft 90whether the larger diameter heating element 100 is connected to thecatheter shaft 90, and adjusting an energy output to a desired energyoutput. Detecting whether the larger diameter heating element 100 isconnected may comprise measuring at least one of a resistance value andan inductance value of the connected heating element by passing a smallcurrent through the connected heating element and determining if thelarger diameter heating element 100 is connected based on the result.And in yet further embodiments, the method may comprise disconnectingthe larger diameter heating element 100 from the catheter shaft 90 andconnecting a third heating element to the shaft, the third heatingelement having a third diameter that is greater than the second diameterD2.

FIGS. 14A and 14B illustrate one embodiment for detecting a type ofcatheter and/or heating segment attached to the power source 18 in orderto adjust the power output from the power source 18 to achieve a desiredtreatment outcome. This embodiment provides a multi-pin connector 119(FIG. 14A) in the handle 16 and a chip 21 (FIG. 14B) that connects tothe multi-pin connector 119. The chip 21 stores information about thecatheter and/or heating segment 15. When the handle 16 is connected tothe power source 18, the power source 18 reads the information stored onthe chip and adjusts power output accordingly. Information stored on thechip 21 may include, for example, control parameters, treatment time,and catheter type information.

The chip 21 may be, for example, an off-the-shelf EPROM-type chip, suchas DS2502+. With reference to FIG. 14B, the chip 21 has at least threepins, including a signal ground pin 23, a communication signal pin 25,and a non-functional pin 27. The functional pins 23, 25 are connected totwo pins 29, 31 of the multi-pin connector 119 of FIG. 14A for datacommunication. The remaining pins of the multi-pin connector 119 may beconnected to various other components. For example, two of the pins 33,35, may be connected to the heating segment 15 for energy delivery, twoof the pins 37, 39, may be connected to a temperature sensor on oradjacent the heating segment 15 for temperature feedback, and two of thepins 41, 43, may be connected to a light source at or adjacent thedistal end 13 of the shaft 12 for external visualization.

As described above, the present embodiments advantageously providetreatment devices having a heating element with a selectable length ordiameter. These embodiments enable the length or diameter of the heatingelement to be changed on the fly during a treatment procedure, without aneed to interrupt the procedure or provide a complete second treatmentdevice. Thus a single catheter may be used at different locations in theHAS by using a shorter heating segment for shorter HAS (such as the STVand some of the SSV) and a longer heating segment for longer HAS (suchas the GSV and some of the SSV), a larger diameter heating segment forlarger veins (such as the GSV and some of the SSV), and a smallerdiameter heating segment for smaller veins (such as some of the SSV andSTV), thus achieving greater efficiency during treatment, fasterprocedure time and better patient outcomes. In addition, theseembodiments may include an “intelligent” power source that is able toautomatically detect the length or diameter of the heating segment andadjust power delivery for a desired energy output, further enhancingefficiency during treatment and achieving better patient outcomes.

In any of the present embodiments, the treatment devices may be includedin a kit that includes the catheter shaft and handle, together with anyof the heating elements or heating assemblies. The power source andcable may be provided separately from the kit. Alternatively, the kitmay also include a cable attached to the handle. The kit may then besealed and sterilized. For example, the kit may be sterilized by aprocedure performed with ethylene oxide (EtO).

Further, in certain embodiments the system may leverage reprocessingconcepts, in that the heating element may be disposable for single useto maintain safety and sterility, while the remaining components, suchas the catheter, power source, handle, and cable, can be cleaned andreused. Reuse of the catheter shaft should reduce operation costs passedon to the patient. The patient incurs only the cost of the new heatingelements or heating assemblies, and not the cost of a new catheter shaftand handle. Specifically, in one embodiment, the heating elements orheating assemblies are discarded after a single use. Thereafter, thecatheter shaft and handle is collected and cleaned. Following cleaning,the used catheter shaft and handle may be repackaged into a kit with newheating elements or heating assemblies, sealed and sterilized. Forexample, the kit containing the cleaned, used catheter shaft and handle,and new heating elements or heating assemblies is subjected to asterilization process using EtO.

In any of the present embodiments, during operation, the power deliveredto the heating element may be automatically adjusted by the power supplybased on a feedback loop. The feedback parameters may be, for example,temperature at the treatment site, or inductance/resistance values atthe treatment site. Such automatic power adjustment facilitatesachieving an effective temperature for vessel ablation.

It is to be understood that the foregoing description is intended toillustrate and not limit the scope of the invention, which is defined bythe scope of the appended claims. Other embodiments are within the scopeof the following claims.

1. An adjustable-dimension catheter for tissue ablation, comprising: anelongate shaft having a distal end and a proximal end; a shaft connectoradjacent the distal end of the shaft, the shaft connector having aplurality of shaft electrical contacts; and a first heating assemblyhaving a first heating element having a first length and a firstdiameter at a distal end thereof, and a first heating element connectoradjacent a proximal end thereof, the first heating element connectorhaving a plurality of first heating element electrical contacts having afirst heating element electrical contact configuration; a second heatingassembly having a second heating element having a second length and asecond diameter at a distal end thereof, and a second heating elementconnector adjacent a proximal end thereof, the second heating elementconnector having a plurality of second heating element electricalcontacts having a second heating element electrical contactconfiguration; wherein the first and second heating element connectorsare selectively connectable to the shaft connector at the distal end ofthe shaft to selectively couple the first and second heating assembliesto the shaft; wherein at least one of the first and second lengths andthe first and second diameters of the first and second heating elementsare different; and wherein the first and second heating elementelectrical contact configurations are different, such that the firstheating element electrical contacts contact a first combination of theshaft electrical contacts of the shaft connector when the first heatingelement connector is connected to the shaft connector, and the secondheating element electrical contacts contact a second combination of theshaft electrical contacts of the shaft connector when the second heatingelement connector is connected to the shaft connector, and the first andsecond combinations of the shaft electrical contacts are different. 2.The catheter of claim 1, wherein the shaft electrical contacts and thefirst and second heating element electrical contacts each have a steppedconfiguration in which the contacts are spaced in the axial directionand at least two of the contacts are spaced in the radial direction. 3.The catheter of claim 1, wherein the heating elements each comprise anelectrically resistive element.
 4. The catheter of claim 3, wherein theelectrically resistive element is a coil.
 5. The catheter of claim 1,further comprising an indicator adjacent a proximal end of the shaftthat indicates which of the first and second heating elements isconnected to the shaft.
 6. An adjustable-dimension catheter for tissueablation, comprising: an elongate shaft having a distal end and aproximal end; a shaft connector adjacent the distal end of the shaft,the shaft connector having a plurality of shaft electrical contacts; anda plurality of heating assemblies, each comprising a heating element ofa different length at a distal end thereof, and each having a heatingelement connector adjacent a proximal end thereof, each of the heatingelement connectors having a plurality of heating element electricalcontacts; wherein the heating element connectors are selectivelyconnectable to the shaft connector at the distal end of the shaft toselectively couple the heating assemblies to the shaft; and wherein theheating element electrical contacts on each of the heating assemblieshave different configurations, such that the heating element electricalcontacts on each of the heating assemblies contact a differentcombination of the shaft electrical contacts of the shaft connectordepending on a length of a given one of the heating elements.
 7. Thecatheter of claim 6, further comprising a power source configured toautomatically detect a length of a connected one of the heating elementsand adjust a level of power delivery for a desired energy output.
 8. Thecatheter of claim 6, wherein the shaft electrical contacts and theheating element electrical contacts each have a stepped configuration inwhich the contacts are spaced in the axial direction and at least two ofthe contacts are spaced in the radial direction.
 9. The catheter ofclaim 6, further comprising a first set of screw threads on the shaftconnector and mating second sets of screw threads on the heating elementconnectors.
 10. The catheter of claim 6, wherein the heating elementseach comprise at least one radio frequency (RF) electrode.
 11. Thecatheter of claim 6, wherein the heating elements each comprise anelectrically resistive element.
 12. The catheter of claim 11, whereinthe heating elements each comprise a different diameter.
 13. Thecatheter of claim 6, further comprising an indicator adjacent a proximalend of the shaft that indicates which of the heating elements isconnected to the shaft.
 14. The catheter of claim 13, wherein theindicator comprises at least one light-emitting diode (LED).
 15. Thecatheter of claim 14, wherein the indicator comprises a plurality ofdifferently colored LEDs. 16-37. (canceled)